A computer network such as a local area network (LAN), a wide area network (WAN), or the Internet facilitates communication among devices (e.g., clients). These devices may include workstations, servers, personal computers, cell phones, PDAs, wireless access points, laptops, and other electronic devices.
Before a client can communicate over or with a network, the client must obtain an Internet Protocol (IP) address. A client may acquire an IP address through, for example, a client-server networking protocol such as, by way of example but not limitation, Bootstrap Protocol (BOOTP) which is a User Datagram Protocol (UDP), Dynamic Host Configuration Protocol (DHCP), that can be used to assign dynamic IP addresses to clients, Point-to-Point Protocol over Ethernet (PPPoE), or some other known or convenient networking protocol.
A network may filter communication to and from a client that has not yet been assigned an IP address. For example, a network may be configured so that one or more Access Control Lists (ACLs) indicate whether to forward or discard a packet or a class of packets. The ACL may be used, by way of example but not limitation, to direct network routers to drop all packets originating from and directed to a client that has not been assigned an IP address.
Filtering mechanisms of the variety described above, however, may consume significant network resources while processing data to and from clients without IP addresses because the packets are not discarded until the routing phase. Moreover, networks using schemes such as ACL configuration to filter packets may unnecessarily complicate decision-making for users and raise additional security issues.